Choroid plexus alterations in autism spectrum disorder: A PET-MRI study.

This brain imaging study looked at fluid-producing structures called the choroid plexus in 36 autistic adults compared to 29 non-autistic people. The researchers found that these brain structures were enlarged in autistic people, with about 30% showing particularly large volumes. In autistic men, larger volumes were linked to more severe autism symptoms, while autistic women showed signs of brain inflammation in these areas. This suggests the immune system in the brain may play a role in autism.

This PET-MRI study examined the choroid plexus (CP) - brain structures involved in cerebrospinal fluid production and immune regulation - in 36 autistic adults versus 29 controls. Researchers measured CP volume and inflammatory markers using advanced neuroimaging. Results showed significantly enlarged CP volume in autistic participants, with approximately 30% having volumes more than 2 standard deviations above the control average. Exploratory sex-specific analyses revealed that larger CP volumes correlated with more severe autism symptoms in males, while elevated inflammatory markers in the CP were observed in autistic females.

These findings provide novel evidence of structural brain differences in autism and suggest potential involvement of neuroinflammatory processes.

Findings suggest neuroinflammatory processes and structural brain differences may contribute to autism. Sex-specific patterns indicate males and females may have different underlying mechanisms. Results support further investigation of choroid plexus as potential biomarker and therapeutic target in autism research.

Study is cross-sectional, limiting causal interpretations. Sex-specific analyses were exploratory. Sample size for subgroup analyses may be limited. Unknown medication effects or other confounding factors. Generalizability beyond the specific adult population studied is unclear.

The choroid plexus (CP), primarily known as the production site of cerebrospinal fluid (CSF), constitutes one of the sites of the blood-CSF barrier and plays a unique role in inflammation propagation, serving as a key regulator of immune responses. Recent work has shown CP enlargement in neurological and psychiatric disorders with immune involvement. To investigate potential neuroimmune and structural alterations in vivo in autism spectrum disorder (ASD), we assessed the CP-localized expression of mitochondrial translocator protein (TSPO) and CP volume in autistic adults. Sixty-five participants, which included 36 autistic participants and 29 non-autistic controls (CON), completed a simultaneous positron emission tomography-magnetic resonance imaging (PET-MRI) scan with the TSPO radiotracer [C]PBR28.

The CP was segmented using subject-level anatomical scans. We observed CP volume enlargement in ASD (mean group difference: 677.8, 95 % CI [331.0, 1025.0], p = 0.0002). In particular, the CP volume of ∼30 % of autistic adults was more than 2 standard deviations above the average CP volume of CON. Exploratory analysis considering sex showed that CP volume was associated with more severe ASD symptoms in autistic males (estimated beta: 153.10, 95 % CI [50.03, 256.30], p = 0.005) and that TSPO in the CP was elevated in autistic females (mean group difference 0.12, 95 % CI [0.03, 0.21], p = 0.01).

Our findings reveal volumetric alterations of the human CP in ASD, providing novel insights into the involvement of the CP in ASD.